Card comprising a paper core and at least one chip incorporated into the paper core and a process for the production thereof.
It is known to produce cards which contain an electronically readable and/or writable chip. Such cards, also known as identity cards, are frequently printed, are used as payment or telephone cards and are usually produced from plastics such as for example PVC, PET or ABS. The chip comprises a digital memory component, the storage capacity of which may vary, and which may be read and/or written either via contacts brought out to the surface of the card or in contactless manner, for example via a coil.
Chips which are suitable for both the contactless variant and that comprising contacts are commercially available. However, cards made from plastics cannot be provided with high quality print and films laminated thereon can be exchanged without leaving visible traces. As a consequence, plastics cards may only insufficiently be protected against tampering with the chip.
It is known from DE 42 18 158 to coat a plastics card with photographic layers. However, the process required for this purpose, in which the photosensitive layers of a photographic material must be peeled off from the support thereof, is highly complex.
Moreover, the stiffness of plastics cards is unpleasant for the user.
A card is described as known in DE 29 20 012 which comprises a unit consisting of a chip with support element, supply lines and external contact surfaces, wherein the unit is rigidly connected with the card. Due to the severe bending loads to which the unit is exposed, this structure is considered unsuitable for practical requirements.
The card according to the invention of DE 29 20 012 differs from the rigid structure in that the unit consisting of chip plus support element is accommodated in a cut-out which is somewhat larger than the unit and the unit is moreover retained in the cutout by a resilient material. The cut-out is intended to be similar in outline to the support element. Preferably, the chip plus support element and contact surfaces is held in the window by cover films laminated onto both sides, wherein the cover film must have punched out portions over the contact surfaces. In order to avoid damaging the chip, which, via the contact surfaces, is in direct thermal contact with the cover films, only cold lamination can be used to apply the films. Films laminated in this manner may, however, be more readily detached than hot-laminated films. In addition, according to DE 29 20 012, the cover films must be stiff, so resulting in unpleasantly rigid cards.
U.S. Pat. No. 4,457,798 discloses a process which involves treating the card inlay at one point in such a manner that a subsequently hot-laminated film does not adhere at this point. This point is then punched out in such a manner that the film remains undamaged and the chip module is inserted and firmly adhered in the resultant indentation. While the process does indeed make it possible to hot-laminate films onto the card inlay, the chip and the contact surfaces are, however, inadequately protected. In addition, residual release agent frequently results in detachment of the cover film and the process is highly elaborate.
The identity cards described in DE 30 299 39 contain an IC component plus support element and connection lines, which component is laminated into the card composite and is bonded with the card on all sides and over its entire surface. In order to make it possible to use hot lamination for this purpose without destroying the chip, the latter must be protected by buffer zones.
While the resultant identity cards do indeed exhibit resistant cover layers, anti-counterfeiting security is still unsatisfactory. In particular, print quality is inadequate.
Known cards do not meet the elevated anti-counterfeiting security requirements of identity cards. For example, the cover films may too easily be removed without damaging the card body, so making it possible to tamper with the chip and other security features and too few different security features are possible.
A further disadvantage of known cards is the inadequate durability thereof, which results in detachment of the cover layer after some time, so in turn permitting tampering. In particular, it is then no longer possible to tell whether the card has been tampered with or has simply been exposed to particularly severe use.
Furthermore, prior art cards are very stiff, contacts brought to the surface are readily worn away and manufacture is very elaborate and thus costly.